Cydia Impactor is a GUI tool for working with Android devices from computers running Windows or Mac OS X. It can be used to reboot the device, enter fastboot mode, access the shell, scan for USB drivers for your device, and a bit more.

But its key feature is to provide root access to many Android devices by exploiting of the Android “Master Key” vulnerability, and if it does not work falling back to a different signature verification bug. There are other tools (e.g. unlockroot, Moborobo,…) or methods to provide root access, but if those do not work or you have troubles installing drivers, Cydia Impactor may be worth a try.

I did try on MK908 and T428 mini PCs in a Windows XP netbook, but for some reasons the software could not detect the USB connection (with USB debug enabled in Android), although Moborobo did. But Benjamin, who tipped me about this application, told me he successfully rooted a Mediatek MTK6577 based phone, as well as a tablet powered by Rockchip RK3066.

If your device firmware has been patched against the two bugs used for the root exploit, you won’t be able to root the device. Currently three device/firmware combinations are known to not be rootable with Cydia Impactor: Motorola Atrix 4D 4.1.1, Huawei Ascend Mate 4.1, and HTC One 4.2.2.

After connecting the phone to your computer via a USB cable, a screen will pop up on your phone asking if you want to allow USB Debugging. Press ok and then run Impactor by selecting the first option (start with #drop) and then click Start.